2008 Outback 2.5 L.L. Bean
Hey do you know if that one you posted will fit an '08 2.5?rear
remove sensor, install this part, then reinstall sensor.
just an example:
O2 Extender Oxygen Sensor Spacer HHO Test Pipe 1 | eBay
there are different lengths and even right angle versions if you need more clearance (will vary by year/model/heat shields...stuff). some folks use two of the shorter ones piggybacked together if one doesn't work.
friend of mine that owns a shop said he's been using the right angle versions as they don't make the sensor + extender so long that they run into things. but i haven't tried the right angle style yet.
it's so easy to do and works so often that i consider this the first step unless there's some compelling reason to work on something else.